The present invention refers to a rotation damper for a so called swing phase control at toggle joint prosthesis. This swing phase control provides a dampening of the forward swing motion of a limited swing angle, which occurs when the lower part of the toggle joint prosthesis, after a finished step, is moved forward rapidly for initiation of the next step. Without such a rotation dampening of the joint the prosthesis bearer will get a bumpy walk, which is not only unnatural, but which also causes increased stress on the prosthesis and body parts cooperating therewith.
For such rotation dampening of toggle joint prostheses in more simple cases earlier have been used dampening rubber blocks and at more sophisticated embodiments, more or less complex hydraulic systems, with valves and pistons of rather small dimensions, which were manufactured with high precision. This means that such earlier rotation dampers have been expensive components, which have often meant intricate sealing problems, in order to prevent the hydraulic fluid from leaking out.